Cal. Prob. Code § 16375 — Apportionment at Beginning and End of Income Interest

(a) An income beneficiary is entitled to net income in accordance with the terms of the trust from the date an income interest begins. The income interest begins on the date specified in the terms of the trust or, if no date is specified, on the date an asset becomes subject to either of the following:

(1) The trust for the current income beneficiary.

(2) A successive interest for a successor beneficiary.

(b) An asset becomes subject to a trust under paragraph (1) of subdivision (a) as follows:

(1) For an asset that is transferred to the trust during the settlor’s life, on the date the asset is transferred.

(2) For an asset that becomes subject to the trust because of a decedent’s death, on the date of the decedent’s death, even if there is an intervening period of administration of the decedent’s estate.

(3) For an asset that is transferred to a fiduciary by a third party because of a decedent’s death, on the date of the decedent’s death.

(c) An asset becomes subject to a successive interest under paragraph (2) of subdivision (a) on the day after the preceding income interest ends, as determined under subdivision (d), even if there is an intervening period of administration to wind up the preceding income interest.

(d) An income interest ends on the day before an income beneficiary dies or another terminating event occurs or on the last day of a period during which there is no beneficiary to which a fiduciary may, or is required to, distribute income.